A bicycle derailleur adjusting apparatus for adjusting a bicycle derailleur includes a controller. The bicycle derailleur includes a base member adapted to be mounted to a bicycle, a movable member, a linkage coupled between the base member and the movable member, and an actuator configured to move the movable member of the bicycle derailleur among a plurality of derailleur positions. The controller is configured to control the actuator based on a travel value indicative of a travel distance of the movable member between adjacent derailleur positions to update the derailleur positions of the movable member.